The Contax 35mm film: full frame uses the Contax/Yashica mount with a 1.00× crop factor (about 36.0 × 24.0 mm sensor). Below: equivalent focal lengths, maximum shutter speeds for sharp stars, a hyperfocal distance chart, compatible lenses and how to check the shutter count.
Equivalent focal length & field of view
| Lens focal length | Full-frame equivalent | Diagonal FOV | Horizontal FOV |
|---|---|---|---|
| 10 mm | 10 mm | 130.4° | 121.9° |
| 12 mm | 12 mm | 122.0° | 112.6° |
| 14 mm | 14 mm | 114.2° | 104.3° |
| 16 mm | 16 mm | 107.0° | 96.7° |
| 18 mm | 18 mm | 100.5° | 90.0° |
| 20 mm | 20 mm | 94.5° | 84.0° |
| 24 mm | 24 mm | 84.1° | 73.7° |
| 28 mm | 28 mm | 75.4° | 65.5° |
| 35 mm | 35 mm | 63.4° | 54.4° |
| 50 mm | 50 mm | 46.8° | 39.6° |
| 85 mm | 85 mm | 28.6° | 23.9° |
| 135 mm | 135 mm | 18.2° | 15.2° |
| 200 mm | 200 mm | 12.3° | 10.3° |
| 300 mm | 300 mm | 8.2° | 6.9° |
| 400 mm | 400 mm | 6.2° | 5.2° |
| 600 mm | 600 mm | 4.1° | 3.4° |
Multiply by the 1.00× crop factor for the full-frame equivalent field of view.
Milky Way exposure: NPF and 500 rule
| Focal length | NPF @ f/1.8 | NPF @ f/2.8 | Strict NPF @ f/2.8 | 500 rule |
|---|---|---|---|---|
| 10 mm | 24.0 s | 27.5 s | 14.8 s | 50.0 s |
| 12 mm | 20.0 s | 22.9 s | 12.3 s | 41.7 s |
| 14 mm | 17.1 s | 19.6 s | 10.6 s | 35.7 s |
| 16 mm | 15.0 s | 17.2 s | 9.3 s | 31.2 s |
| 18 mm | 13.3 s | 15.3 s | 8.3 s | 27.8 s |
| 20 mm | 12.0 s | 13.8 s | 7.4 s | 25.0 s |
| 24 mm | 10.0 s | 11.5 s | 6.2 s | 20.8 s |
| 28 mm | 8.6 s | 9.8 s | 5.3 s | 17.9 s |
| 35 mm | 6.9 s | 7.9 s | 4.3 s | 14.3 s |
| 50 mm | 4.8 s | 5.5 s | 3.0 s | 10.0 s |
NPF = (35 × f-number + 30 × pixel pitch) ÷ focal length, with a pixel pitch of 5.9 µm (typical for this format — exact resolution not in our database). The strict version (Michaud's detailed NPF for the galactic core) gives pin-point stars at 100% view; the 500 rule is a loose rule of thumb that shows trailing on modern sensors.
Hyperfocal distance chart
| Focal length | f/2.8 | f/5.6 | f/8 | f/11 | f/16 |
|---|---|---|---|---|---|
| 14 mm | 2.3 m | 1.2 m | 0.8 m | 0.6 m | 0.4 m |
| 16 mm | 3.1 m | 1.5 m | 1.1 m | 0.8 m | 0.5 m |
| 18 mm | 3.9 m | 1.9 m | 1.4 m | 1.0 m | 0.7 m |
| 20 mm | 4.8 m | 2.4 m | 1.7 m | 1.2 m | 0.9 m |
| 24 mm | 6.9 m | 3.5 m | 2.4 m | 1.8 m | 1.2 m |
| 28 mm | 9.4 m | 4.7 m | 3.3 m | 2.4 m | 1.7 m |
| 35 mm | 15 m | 7.3 m | 5.1 m | 3.7 m | 2.6 m |
| 50 mm | 30 m | 15 m | 10 m | 7.6 m | 5.3 m |
Focus at the hyperfocal distance and everything from half that distance to infinity is acceptably sharp (circle of confusion 0.03 mm). Use the hyperfocal calculator for other settings.
Compatible lenses (9 in our database)
| Lens | Focal length | Max aperture | Mount |
|---|---|---|---|
| Contax Zeiss 21mm f/2.8 Distagon | 21 mm | f/2.8 | Contax/Yashica |
| Contax Zeiss 28mm f/2.8 Distagon | 28 mm | f/2.8 | Contax/Yashica |
| Sun Wide Zoom Macro 24-40mm f/3.5 | 24–40 mm | f/3.5 | M42, Pentax K |
| Miranda 28mm f/2.8 MC | 28 mm | f/2.8 | Contax/Yashica, Canon FD |
| Yashica ML 50mm f/1.7 | 50 mm | f/1.7 | Contax/Yashica |
| Yashica ML 50mm f/2 | 50 mm | f/2 | Contax/Yashica |
| Yashica DSB 55mm f/2 | 55 mm | f/2 | Contax/Yashica |
| Yashica ML 55mm F/4 Macro | 55 mm | f/4 | Contax/Yashica |
| Zeiss Carl Zeiss Sonnar T* 180mm f/2.8 MMJ | 180 mm | f/2.8 | Contax/Yashica |
Native and adapter-free compatible lenses from the Lensfun database. Third-party and adapted lenses may also work.
How to check the Contax 35mm film: full frame shutter count
Not every maker writes a shutter count into image files. Try `exiftool -a -G1 -s image` on an unedited original and look for a tag containing "Shutter" or "Count".
ExifTool tag: (varies). Always test an original, unedited file straight from the card.
Where to buy
Compare new and used prices at these retailers:
B&H PhotoAmazonKEH (used)MPB (used)